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Background: The litchi fruit borer Conopomorpha sinensis Bradley is a major destructive pest of litchi and longan plants in China, India and South East Asia. Given its strong olfactory-based oviposition behaviour, interfering with the chemical communication between this insect pest and its host plant may serve as a potential control strategy. However, the chemical compounds associated with its egg-laying behaviour remain poorly understood., Results: In this study, we investigated the olfactory preference of female C. sinensis for oviposition on intact mature fruits of the Feizixiao (FZX) and Guiwei (GW) varieties. Results showed that female C. sinensis preferred to lay eggs on FZX compared with GW fruits, and this preference was olfactory-induced. In addition, we identified differences in the chemical composition of the volatile blend and proportions between FZX and GW fruits, with terpenes being the main volatile components contributing to this divergence. Compounds that induced electrophysiological activity in female borers were subsequently screened from FZX. d-Limonene exhibited the strongest oviposition attraction among four candidates. Furthermore, this compound served as a volatile olfactory cue for recognition and orientation in female C. sinensis., Conclusion: The results of this study provide a deeper understanding of the olfactory preferences of female C. sinensis for oviposition on specific litchi varieties. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Litchi (Litchi sinensis), a fruit with a sweet and white aril, cultivated mainly in Southeast Asia and possesses anticancer, antibacterial, antioxidant, and other therapeutic properties. It is a delicacy among children. However, an outbreak of acute encephalopathy syndrome (AES) in litchi growing regions during the seasons of litchi ripening and harvesting (May-June) resulted in symptoms of lethargy, weakness, fever, vomiting, seizures, and coma that was most common among malnourished children below 15 years. Upon successful epidemiological studies, it was confirmed that the non-protein amino acids such as hypoglycine A (HGA) and methylenecyclopropylglycine (MCPG) are responsible for the AES outbreak. Most of the underprivileged and malnourished kids with an empty stomach venture into the litchi orchards to savor the fruit during the litchi harvesting season. Their fasting condition results in decreased glucose levels in the blood. The decreased glucose levels trigger glycogenolysis. However, gluconeogenesis takes over glycogenolysis to replenish the glucose levels due to fewer glycogen stores in malnourished children. The toxins are involved in fatty acid oxidation and gluconeogenesis pathways, by blocking several steps in the former process. Depleted glycogen stores and suppression of gluconeogenesis synergistically cause hypoglycemia and accumulation of toxic intermediates from the metabolic pathway leading to metabolic failure. The incidence of AES can be prevented by creating proper awareness among the farmers, vendors and consumers on the importance of adverse effects of litchi fruit when consumed on empty stomach or fasting state. Further, elucidating detailed biochemical pathway of HGA and MCPG toxicity, improving agricultural and public health practices, keeping glucose stores and glucose banks in the areas which are highly prone to litchi induced toxicity are some of the therapeutic measures. This review highlights and discusses the AES incidences, mechanistic pathways involved in litchi fruit toxicity, and corresponding risk factors involved and possible treatment and preventive approaches., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Magnetic nanometer combined with microwave thawing (MN-MT) could become a novel solution to challenges uneven and overheating of microwave thawing (MT), while retaining high thawing efficiency, compared to conventional water immersion thawing (WT). In this study, MN-MT was applied to thaw fruit (lychee as an example) for the first time, and was evaluated by comparison with WT, MT and water immersion combined with microwave thawing (WI-MT). Results showed that MN-MT could significantly shorten the thawing time of frozen lychee by 80.67%, 25.86% and 18.83% compared to WT, MT and WI-MT, respectively. Compared to WT, MN-MT was the only thawing treatment which significantly enhanced the release of quercetin-3-O-rutinose-7-O-α-l-rhamnoside, according to HPLC-DAD. Meanwhile, thermal-sensitive procyanidin B2, phenylpropionic acid and protocatechuic acid were found to be protected from degradations only by MN-MT based on UPLC-ESI-QTOF-MS/MS results. In summary, MN-MT is a potential novel treatment for rapid thawing and quality maintenance of frozen fruits., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Fruit acidity determines the organoleptic quality and nutritive value of most fruits. In litchi, although the organic acid composition of pulps is known, the molecular mechanisms and genes underlying variation in fruit acidity remain elusive. Herein, developing pulps of two contrasting litchi varieties, Huaizhi (HZ, low-acidity) and Boye_No.8 (B8, high-acidity), were subjected to metabolomics and transcriptomics, and the dynamic metabolome and transcriptional changes were determined. Measurements revealed that the dominant acidity-related organic acid in litchi pulps is malate, followed in low levels by citrate and tartrate. Variation in litchi pulps' acidity is mainly associated with significant differences in malate and citrate metabolisms during fruit development. Malic acid content decreased by 91.43% and 72.28% during fruit ripening in HZ and B8, respectively. The content of citric acid increased significantly in B8, while in HZ it was reduced considerably. Differentially accumulated metabolites and differentially expressed genes analyses unveiled fumarate, succinate, 2-oxoglutarate, GABA (γ-aminobutyric acid), phosphoenolpyruvate, and citrate metabolisms as the key driving pathways of litchi fruits' acidity variation. The drastic malate and citrate degradation in HZ was linked to higher induction of fumarate and GABA biosynthesis, respectively. Thirty candidate genes, including three key genes ( LITCHI026501.m2 , fumarase; LITCHI020148.m5 , glutamate decarboxylase; and LITCHI003343.m3 , glutamate dehydrogenase), were identified for functional studies toward genetic modulation of litchi fruit acidity. Our findings provide insights into the molecular basis of acidity variation in litchi and provide valuable resources for fruit quality improvement.

The perception that many fruit wastes, particularly the peel, contain more phytochemicals than the edible portions has been largely supported by scientific evidence, making them potential sources of bioactive and therapeutic phytochemicals. The peel and seed of Litchi (Litchi chinensis Sonn.) contain bioactive principles and have been shown to exhibit antioxidative, antidiabetic, cancer preventive, anti-obesogenic, and anti-inflammatory properties. This review presents a critical analysis of previous and current perspectives on the medicinal, toxicological, and phytochemical profiles of litchi fruit peel and seed, thus providing an evidence-based platform to explore their medicinal potential. A literature search was done on "PubMed," "Google Scholar," and "ScienceDirect." Peer-reviewed published data on the medicinal profiles of litchi fruit peel and seed were identified and critically analyzed. The fruit peel and seed improved glycemic control and insulin signaling and downregulated lipogenic and cholesterogenic processes. Their neuroprotective, hepatoprotective, and renal protective potentials were influenced by antioxidative and anti-inflammatory actions. The anticancer effect was mediated by upregulated proapoptotic, proinflammatory, antiproliferative, and anti-metastatic processes in cancer cells. Simple flavonols, sesquiterpenes, phenolic acids, jasmonates, and proathocyanidins are the possible bioactive principles influencing the medicinal effects. Appropriate toxicity studies are, however, still lacking. Litchi fruit wastes may be further studied as useful sources of therapeutic agents that may have medicinal relevance in oxidative, metabolic, vascular, and carcinogenic ailments. PRACTICAL APPLICATIONS: Underutilized fruit wastes contribute to environmental pollution. Interestingly, these wastes contain phytochemicals that could be of medicinal relevance if their medicinal potentials are maximized. Litchi fruit is a widely consumed fruit with commercial value. Its peel and seeds contribute to fruit wastes. The review exposes the medicinal potential and bioactive principles and/or nutrients of the fruit's peel and seed while elucidating the underlying therapeutic mechanisms or modes of actions through which litchi peel and seed potentiate medicinal effects. Thus, the review provides an evidence-based platform to explore the medicinal potential of underutilized wastes from litchi fruit. Additionally, the fruit peel and seed could be low-cost residues that could afford ecofriendly opportunity if their medicinal potentials are properly maximized., (© 2021 Wiley Periodicals LLC.)

Cellulases play important roles in the shedding of plant organs; however, little is yet known about the functions of cellulase genes during the process of organ abscission. Abnormal fruitlet abscission is a serious problem in the production of litchi (Litchi chinensis), an economically important fruit widely grown in South Asia. In this study, two abscission-accelerating treatments (carbohydrate stress and application of ethephon) were evaluated in litchi fruitlets. Cell wall degradation and cell separation were clearly observed in the abscission zones of treated fruitlets, consistent with enhanced cellulase activities and reduced cellulose contents. The expression of two cellulase genes (LcCEL2 and LcCEL8) was strongly associated with abscission. Floral organs of transgenic Arabidopsis overexpressing LcCEL2 or LcCEL8 showed remarkably precocious abscission. Electrophoretic mobility shift assays and transient expression experiments demonstrated that a novel homeodomain-leucine zipper transcription factor, LcHB2, could directly bind to and activate HD-binding cis-elements in the LcCEL2 and LcCEL8 promoters. Our results provide new information regarding the transcriptional regulation of the cellulase genes responsible for cell wall degradation and cell separation during plant organ shedding, and raise the possibility of future manipulation of litchi fruitlet abscission by modulation of the activities of these two cellulases., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

Fruit cracking is a serious problem in Litchi chinensis cv. Baitangying orchards, but few advances have been made in understanding the molecular basis of cracking susceptibility in 'Baitangying'. In this work, we conducted transcriptome and quantitative proteome analyses of the pericarps of three kinds of litchi: noncracking 'Feizixiao' (cracking-resistant cultivar, F), noncracking 'Baitangying' (B), and cracking 'Baitangying' (CB). A total of 101 genes and 14 proteins with the same regulatory changes were found to overlap between CB vs. B and B vs. F, and we focused on these results to avoid the effects of passive progression after fruit cracking. The obtained data suggest that fruit cracking susceptibility in 'Baitangying' is related to pericarp photosynthetic characteristics and the oxidation of unsaturated fatty acids in this cultivar, which lead to changes in cuticle structure. Furthermore, differences in the pericarp hormone balance between 'Baitangying' and 'Feizixiao' may influence the susceptibility of 'Baitangying' to fruit cracking. This integrated analysis of transcriptomic and proteomic data indicates that susceptibility to fruit cracking in 'Baitangying' litchi is regulated both translationally and posttranslationally. Our results may help provide a new perspective for further study of the mechanisms that govern fruit cracking susceptibility in 'Baitangying' litchi and other fruits., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Starch was isolated from the kernels of jackfruit, longan, loquat, litchi, and mango fruits, which contained approximately 56, 59, 71, 53, and 64% starch, respectively, indicating that these fruit kernels are good starch sources. The structural and functional properties of these isolated starches were investigated and compared. The starches had irregular, truncated, spherical, and elliptical shapes with central hila and exhibited different sizes, with mango starch being the largest and jackfruit and longan starches being the smallest. The five starches had similar amylose contents but exhibited significantly different crystalline properties including crystalline type, relative crystallinity, short-range ordered structure, and lamellar intensity. Among the five starches, the jackfruit and loquat starches had the highest and lowest gelatinization temperature and enthalpy, respectively, and the litchi and mango starches had the highest and lowest pasting viscosity, respectively. The longan and loquat starches were more susceptible to enzyme hydrolysis than the other starches., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Senescence is a key factor resulting in deterioration of non-climacteric fruit. NAC transcription factors are important regulators in plant development and abiotic stress responses, yet little information regarding the role of NACs in regulating non-climacteric fruit senescence is available. In this study, we cloned 13 NAC genes from litchi (Litchi chinensis) fruit, and analyzed subcellular localization and expression profiles of these genes during post-harvest natural and low-temperature-delayed senescence. Of the 13 NAC genes, expression of LcNAC1 was up-regulated in the pericarp and pulp as senescence progressed, and was significantly higher in senescence-delayed fruit than that in naturally senescent fruit. LcNAC1 was induced by exogenous ABA and hydrogen peroxide. Yeast one-hybrid analysis and transient dual-luciferase reporter assay showed that LcNAC1 was positively regulated by the LcMYC2 transcription factor. LcNAC1 activated the expression of LcAOX1a, a gene associated with reactive oxygen species regulation and energy metabolism, whereas LcWRKY1 repressed LcAOX1a expression. In addition, LcNAC1 interacted with LcWRKY1 in vitro and in vivo. These results indicated that LcNAC1 and LcWRKY1 form a complex to regulate the expression of LcAOX1a antagonistically. Taken together, the results reveal a hierarchical and co-ordinated regulatory network in senescence of harvested litchi fruit., (© The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Consumption of ackee (Blighia sapida) and lychee (Litchi chinensis) fruit has led to severe poisoning. Considering their expanded agricultural production, toxicological evaluation has become important. Therefore, the biochemical effects of eating 1 g/kg canned ackee, containing 99.2 μmol/kg hypoglycin A, and 5 g/kg canned lychee, containing 1.3 μmol/kg hypoglycin A, were quantified in a self-experiment. Using ultra-high-performance liquid chromatography/mass spectrometry, hypoglycin A, methylenecyclopropylacetyl-glycine, and methylenecyclopropylformyl-glycine, as well as the respective carnitine conjugates, were found in urine after ingesting ackee. Hypoglycin A and its glycine derivative were also present in urine after eating lychee. Excretion of physiological acyl conjugates was significantly increased in the ackee experiment. Ingestion of ackee led to up to 15.1 nmol/L methylenecyclopropylacetyl-glycine and traces of methylenecyclopropylformyl-carnitine in the serum. These compounds were not found in the serum after eating lychee. Hypoglycin A accumulated in the serum in both experiments.

'Gola' litchi fruits were stored under ten different CA-combinations at 5±1°C to investigate its effects on pericarp browning, biochemical quality and antioxidative activities. Control fruit turned completely brown after 28days of storage and were excluded from the study. Fruit-stored under CA7-combination (1% O2+5% CO2) showed reduced weight loss, pericarp browning, membrane leakage and malondialdehyde contents. Soluble solid contents, titratable acidity and ascorbic acid contents were higher in CA7-stored fruit. Activities of catalase and superoxide dismutase enzymes, levels of total anthocyanins, DPPH radical-scavenging-activity and phenolic contents were significantly higher in CA7-stored litchi fruit. In contrast, activities of polyphenol oxidase and peroxidase enzymes were substantially lower in fruit kept under CA7-combination. Fruit subjected to CA7-conditions also maintained higher organoleptic quality. In conclusion, 1% O2+5% CO2 CA-conditions delayed pericarp browning, maintained antioxidative activities and biochemical characteristics along with better organoleptic quality of litchi fruit for 35days., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Methylenecyclopropylglycine (MCPG) and hypoglycin A (HGA) are naturally occurring amino acids found in some soapberry fruits. Fatalities have been reported worldwide as a result of HGA ingestion, and exposure to MCPG has been implicated recently in the Asian outbreaks of hypoglycemic encephalopathy. In response to an outbreak linked to soapberry ingestion, the authors developed the first method to simultaneously quantify MCPG and HGA in soapberry fruits from 1 to 10 000 ppm of both toxins in dried fruit aril. Further, this is the first report of HGA in litchi, longan, and mamoncillo arils. This method is presented to specifically address the laboratory needs of public-health investigators in the hypoglycemic encephalitis outbreaks linked to soapberry fruit ingestion.

The purpose of this paper was to explore the utility of an electronic nose to detect the quality of litchi fruit stored in different environments. In this study, a PEN3 electronic nose was adopted to test the storage time and hardness of litchi that were stored in three different types of environment (room temperature, refrigerator and controlled-atmosphere). After acquiring data about the hardness of the sample and from the electronic nose, linear discriminant analysis (LDA), canonical correlation analysis (CCA), BP neural network (BPNN) and BP neural network-partial least squares regression (BPNN-PLSR), were employed for data processing. The experimental results showed that the hardness of litchi fruits stored in all three environments decreased during storage. The litchi stored at room temperature had the fastest rate of decrease in hardness, followed by those stored in a refrigerator environment and under a controlled-atmosphere. LDA has a poor ability to classify the storage time of the three environments in which litchi was stored. BPNN can effectively recognize the storage time of litchi stored in a refrigerator and a controlled-atmosphere environment. However, the BPNN classification of the effect of room temperature storage on litchi was poor. CCA results show a significant correlation between electronic nose data and hardness data under the room temperature, and the correlation is more obvious for those under the refrigerator environment and controlled-atmosphere environment. The BPNN-PLSR can effectively predict the hardness of litchi under refrigerator storage conditions and a controlled-atmosphere environment. However, the BPNN-PLSR prediction of the effect of room temperature storage on litchi and global environment storage on litchi were poor. Thus, this experiment proved that an electronic nose can detect the quality of litchi under refrigeratored storage and a controlled-atmosphere environment. These results provide a useful reference for future studies on nondestructive and intelligent monitoring of fruit quality.

A new magnetic bioadsorbent, magnetic litchi peel (MLP), was synthesized by coating powdered litchi peel with Fe3O4, and was used for removing Pb(II) from aqueous solutions. The influencing factors, adsorption isotherms, kinetics, and thermodynamics of Pb(II) adsorption by MLP were investigated using batch assays. Optimum Pb(II) adsorption by MLP was achieved using a contact time of 120 min, an adsorbent dose of 5 g/L, and pH of 6.0. The adsorption equilibrium data conformed to the Langmuir isotherm model, yielding a maximum Pb(II) adsorption capacity of 78.74 mg/g. The adsorption kinetics for Pb(II) adsorption by MLP followed a pseudo-second-order model. The thermodynamic results suggested that Pb(II) adsorption by MLP was spontaneous and exothermic. Additionally, the magnetic adsorbent was easily and rapidly separated out of solution under an external magnetic field., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The adsorption of Cu(II) onto raw litchi pericarp (LP) and modified litchi pericarp (MLP) as a function of pH, adsorbent dose and contact time, were investigated. Adsorption equilibrium isotherms, kinetics, and thermodynamics were studied to characterize the adsorption process. Leaching assays were also conducted to evaluate the potential contamination risk of LP and MLP to aqueous systems. The maximum adsorption of Cu(II) onto MLP was occurred at the pH of 6.0, adsorbent dose of 10.0 g/L, and contact time of 60 min, respectively. The adsorption process of Cu(II) onto LP and MLP were described well by both Langmuir and Freundlich isotherms, and the adsorption kinetics of Cu(II) on MLP was pseudo-second-order. Cu(II) adsorption onto LP and MLP are both exothermic, while it is spontaneous for MLP, and non-spontaneous for LP. The maximum adsorption capacity of Cu(II) onto MLP was 23.70 mg/g, which was about 2.7 times higher than that of LP. Additionally, as compared to LP, the leaching amounts of TOC, TN, and TP from MLP were significantly reduced by a percentage of 27.0%, 90.3%, and 35.3%, respectively., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Our previous work exhibited Aspergillus awamori fermentation of the litchi pericarp increased significantly antioxidant activity and DNA protection effect. In this present study, the litchi pericarp and its aqueous-organic extracted residues were fermented by A. awamori in order to elucidate the enhanced beneficial effects. The study identified that rutin which present in litchi pericarp could be deglycosylated to form quercetin and quercetin-3-glucoside after the fermentation. Application the standard compounds (rutin, quercetin 3-glucoside, quercetin, kaempferol-3-glucoside and kaempferol) further revealed the effective biotransformation by A. awamori fermentation. It was hypothesised that rutin was initially dehydroxylated to form kaempferol-3-rutinoside and then deglycosylated to form kaempferol-3-glucoside and kaempferol. To our best knowledge, it is the first report on dehydroxylated effect of polyphenols caused by A. awamori fermentation. Thus, A. awamori fermentation can provide an effective way to produce health benefiting value-added products from litchi pericarp in food industry., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The effects of vapor pressure deficit (VPD) on litchi fruit quality have not yet been fully defined. The aim of this study was to detail the changes in physiology, sugars, organic acids, and individual anthocyanin concentrations in imported litchi fruit held at various controlled relative humidity (RH) and VPD levels. SO(2)-fumigated (but not acid-treated) litchi imported from Thailand (cv. Kom) and from Israel (cv. Mauritius) were air freighted to the United Kingdom and then stored for 9 days at either 5 or 13 degrees C to simulate shelf-life conditions. Fruits were stored under a series of controlled RH conditions for the duration of the trial using different concentrations of glycerol in deonized water. Respiration rates and weight losses of both fruit lots were greater in litchi stored at 13 degrees C and a VPD of 0.274 kPa. At 5 degrees C and a VPD of 0 or 0.042 kPa, sugars and organic acids in aril and pericarp tissue and individual anthocyanins in pericarp were better maintained. This is the first piece of work that has systematically evaluated the effect of a series of VPDs on litchi fruit biochemistry such that implications for designing systems to better maintain the physiological quality of imported litchi fruit are discussed.

The objective of this study was to create a French database on the polyphenol content of fruit and vegetables as uncooked fruits and vegetables and then to evaluate polyphenol intake through fruit and vegetable consumption in France. To achieve this, we used the Folin-Ciocalteu method adapted to fruit and vegetable polyphenol quantitation (1). Vegetables with the highest polyphenol concentration were artichokes, parsley, and brussels sprouts [>250 mg of gallic acid equivalent (GAE)/100 g fresh edible portion (FEP)]; fruits with the highest concentrations were strawberries, lychees, and grapes (>180 mg of GAE/100 g FEP). Conversely, melons (Cantaloupe cv.) and avocados had the lowest polyphenol concentration for fruits and vegetables, respectively. Based on fruit consumption data, apples and strawberries are the main sources of polyphenols in the French diet, whereas potatoes, lettuces, and onions are the most important vegetable sources. Total polyphenol intake from fruit is about 3 times higher than from vegetables, due to the lower polyphenol concentration in vegetables. The calculation of polyphenol intake, based on both assessment methods used [(Société d'Etudes de la Communication, Distribution et Publicité (SECODIP) and Supplémentation en Vitamines et Minéraux Antioxydants (SUVIMAX)], showed that apples and potatoes provide approximatively half of the total polyphenol intake from fruit and vegetables in the French diet.

The new ascogenous yeast species Issatchenkia hanoiensis was discovered in the frass of the litchi fruit borer Conopomorpha cramerella Snellen. The yeast forms unconjugated persistent asci containing one to two roughened ascospores. The yeast has a CoQ-7 system, which is typical for the genus Issatchenkia. The closest species to I. hanoiensis as indicated by analysis of the partial ribosomal DNA large-subunit (D1/D2) sequence is the asexual species Candida pseudolambica. The two share 94.2% similarity in the sequenced region. Other species of Issatchenkia were also among the closest relatives of I. hanoiensis, the level of similarity ranging from 89.8% to 94.1%. The type culture is strain HB1.3.13=CBS 9198=NRRL Y-27509.

The accurate detection of litchi fruit cluster is the key technology of litchi picking robot. In the natural environment during the day, due to the unstable light intensity, uncertain light angle, background clutter and other factors, the identification and positioning accuracy of litchi fruit cluster is greatly affected. Therefore, we proposed a method to detect litchi fruit cluster in the night environment. The use of artificial light source and fixed angle can effectively improve the identification and positioning accuracy of litchi fruit cluster. In view of the weak light intensity and reduced image features in the nighttime environment, we proposed the YOLOv8n-CSE model. The model improves the recognition of litchi clusters in night environment. Specifically, we use YOLOv8n as the initial model, and introduce the CPA-Enhancer module with chain thinking prompt mechanism in the neck part of the model, so that the network can alleviate problems such as image feature degradation in the night environment. In addition, the VoVGSCSP design pattern in Slimneck was adopted for the neck part, which made the model more lightweight. The multi-scale linear attention mechanism and the EfficientViT module, which can be deeply divided, further improved the detection accuracy and detection rate of YOLOv8n-CSE. The experimental results show that the proposed YOLOv8n-CSE model can not only recognize litchi clusters in the night scene, but also has a significant improvement over previous models. In mAP@0.5 and F1, YOLOv8n-CSE achieved 98.86% and 95.54% respectively. Compared with the original YOLOv8n, RT-DETR-l and YOLOv10n, mAP@0.5 is increased by 4.03%, 3.46% and 3.96%, respectively. When the number of parameters is only 4.93 m, F1 scores are increased by 5.47%, 2.96% and 6.24%, respectively. YOLOv8n-CSE achieves an inference time of 36.5ms for the desired detection results. To sum up, the model can satisfy the criteria of the litchi cluster detection system for extremely accurate nighttime environment identification. [ABSTRACT FROM AUTHOR]

Background: Litchi (Litchi chinensis) is an important sub-tropical fruit in the horticulture market in China. Breeding for improved fruit characteristics is needed for satisfying consumer demands. Budding is a sustainable method for its propagation. During our ongoing breeding program, we observed a litchi mutant with flat leaves and sharp fruit peel cracking in comparison to the curled leaves and blunt fruit peel cracking fruits of the mother plant. Methods: To understand the possible molecular pathways involved, we performed a combined metabolome and transcriptome analysis. Results: We identified 1,060 metabolites in litchi leaves and fruits, of which 106 and 101 were differentially accumulated between the leaves and fruits, respectively. The mutant leaves were richer in carbohydrates, nucleotides, and phenolic acids, while the mother plant was rich in most of the amino acids and derivatives, flavonoids, lipids and organic acids and derivatives, and vitamins. Contrastingly, mutant fruits had higher levels of amino acids and derivatives, carbohydrates and derivatives, and organic acids and derivatives. However, the mother plant's fruits contained higher levels of flavonoids, scopoletin, amines, some amino acids and derivatives, benzamidine, carbohydrates and derivatives, and some organic acids and derivatives. The number of differentially expressed genes was consistent with the metabolome profiles. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway-enriched gene expressions showed consistent profiles as of metabolome analysis. Conclusion: These results provide the groundwork for breeding litchi for fruit and leaf traits that are useful for its taste and yield. [ABSTRACT FROM AUTHOR]

Pericarp browning is the key factor for the extension of shelf life and the maintenance of the commercial value of harvested litchi fruit. Water loss is considered a leading factor of pericarp browning in litchi fruit. In this study, based on the distinct structure of litchi fruit, which is a special type of dry fruit with the aril as the edible part, the effects of water supply via pedicel (WSP) treatment on pericarp browning and the fruit quality of litchi were investigated. Compared with the packaging of the control fruit at 25 °C or 4 °C, the WSP treatment was found to significantly reduce pericarp browning and the decay of litchi fruit. The WSP-treated fruit had a higher L* value, total anthocyanin content, and pericarp water content, and the pericarp was thicker. The WSP treatment significantly suppressed the increase in the electrolyte leakage of the pericarp and maintained higher ascorbic acid (AA) contents in the aril. In addition, the WSP treatment was effective in reducing the activity and gene expression of browning-related genes Laccase (ADE/LAC) and Peroxidase (POD) during the storage period. In conclusion, the WSP treatment could be an effective method to delay pericarp browning and maintain the quality of harvested litchi fruit, and this further supports that litchi fruit has dry fruit characteristics. [ABSTRACT FROM AUTHOR]

Litchi is a fruit of significant commercial value; however, its quality and yield are hindered by downy blight disease caused by Peronophythora litchii. In this study, volatile organic compounds (VOCs) from Streptomyces abikoensis TJGA-19 were investigated for their antifungal effects and studied in vitro and in planta for the suppression of litchi downy blight disease in litchi leaves and fruits. The growth of P. litchii was inhibited by VOCs produced by TJGA-19 cultivated on autoclaved wheat seeds for durations of 10, 20, or 30 days. Volatiles from 20-day-old cultures were more active in inhibition effect against P. litchii than those from 10- or 30-day-old cultures. These volatiles inhibit the growth of mycelia, sporulation, and oospore production, without any significant effect on sporangia germination. Additionally, the VOCs were effective in suppressing disease severity in detached litchi leaf and fruit infection assays. With the increase in the weight of the wheat seed culture of S.abikoensis TJGA-19, the diameters of disease spots on leaves, as well as the incidence rate and disease indices on fruits, decreased significantly. Microscopic results from SEM and TEM investigations showed abnormal morphology of sporangia, mycelia, and sporangiophores, as well as organelle damage in P. litchii caused by VOCs of TJGA-19. Spectroscopic analysis revealed the identification of 22 VOCs produced by TJGA-19, among which the most dominant compound was 2-Methyliborneol. These findings indicated the significant role of TJGA-19 compounds in the control of litchi downy blight disease and in improving fruit quality. [ABSTRACT FROM AUTHOR]

[Objective]By comparing the differences in cell wall components among litchi varieties with different susceptibility to fruit cracking, the study aims to investigate the effects of exogenous application of auxin analogue 2,4-D on the cell wall composition of pericarp and fruit cracking, and to further explore the relationship between the cell wall synthesis metabolism and fruit cracking incidence.[Methods]The changes in carbohydrate contents of two easily cracked litchi varieties (‘Guiwei’ and ‘Nuomici’) and two not easily-cracked litchi varieties (‘Huaizhi’ and ‘Lingfengnuo’) after 75 days of flowering were compared, and the tissue structure and lignin distribution of the pericarps at the 60-85 d after flowering were observed. Fruit clusters of ‘Nuomici’ in two orchards were dipped into auxin analog 2, 4-D, and the soluble sugar contents in the pericarps were determined by GC-MS. The starch and structural carbohydrate contents of the samples were detected by using a spectrophotometer. Transmission electron microscopy and lignin staining were used to observe the tissue structure of litchi pericarp.[Result]The contents of hexose including fructose, glucose and galactose in the pericarp of cracking susceptible variety ‘Nuomici’ were significantly lower than those of low-cracking varieties ‘Huaizhi’ and ‘Lingfengnuo’. A complicate relationship between pectin contents and fruit cracking susceptibility was found. In the pericarp of ‘Nuomici’, the pectin content was only around 1.7 mg/g. And the fruit was bigger and susceptible to cracking. While in the cracking susceptible smaller fruit variety ‘Guiwei’, the pericarp contained high pectin (4.0 mg/g). 2,4-D treatment only temporarily increased the fruit setting rate of litchi in the early stage, but it had no significant impact on the final fruit setting rate. 2,4-D treatment could lead to an increase in the number of layers of pericarp cells and the blurring of the contour of inner pericarp cells; Compared with the control, the treatment with 40 mg/L 2,4-D resulted in an increase in pectin content, thickening of cell walls, and an increase in fruit cracking rate.[Conclusion]There are significant differences in the contents of carbohydrates in the pericarps of litchi varieties with different susceptibility to fruit cracking. Pectin may play a dual role in litchi fruit cracking. The development of pericarp requires dynamic changes in pectin synthesis and degradation. Pectin might play dual role in the cracking of litchi fruit. High pectin in the pericarp results in low expansion, smaller fruit size and higher cracking rate; while low pectin results in higher pericarp expansion, larger fruit size and higher cracking rate. 2,4-D treatment show no significant effect on the final fruit setting rate but will increase the risk of fruit cracking. [ABSTRACT FROM AUTHOR]

【Objective】This study aimed to investigate and analyze the correlation between the quality of fruitbearing shoots in ‘Xianjinfeng’ litchi and fruit setting and fruit quality. Tthe effects of different quality fruit-bearing shoots on fruit setting and quality were compared. The quantitative standard of high quality fruit branches was put forward to provide reference for the development of strong fruit branches in production.【Method】During the key phenological period, the quality indicators of fruit-bearing shoots in ‘Xianjinfeng’ litchi, including length, diameter, and number of leaves, were measured and statistically analyzed. Number of initial fruit setting and final fruit setting with fruit quality were also assessed. Violin plots, Pearson correlation coefficients, and one-way ANOVA were utilized to analyze the distribution, correlation, and significance of the data, as well as to compare the differences in fruit setting and quality among fruit-bearing shoots of different qualities.【Result】The length, diameter, and number of leaves of fruit-bearing shoots in ‘Xianjinfeng’ litchi were concentrated within the ranges of 10.2-14.5 cm, 0.4-0.5 cm, and 28-38 leaves, respectively. The number of initial fruit setting exhibited a significant positive correlation with the diameter of the mother branches, while the final fruit setting rate showed a significant positive correlation with both length and diameter. The correlation between the length, diameter, and number of leaves of fruit-bearing shoots and the same fruit quality traits was generally consistent, either positively or negatively correlated. Notably, single fruit weight demonstrated a significant positive correlation with diameter, while TSS (Total Soluble Solids) and TSS/TA (Total Soluble Solids/Titratable Acidity) showed a significant positive correlation with the number of leaves. Fruit-bearing shoots with a length greater than 14.5 cm exhibited the highest initial fruit setting number (16.95 fruits) and final fruit setting rate (20.73%). Fruit-bearing shoots with a diameter greater than 0.5 cm exhibited the highest initial fruit setting number (15.48 fruits), final fruit setting rate (28.03%), single fruit weight (26.28 g), and edible rate (70.95%). Fruit-bearing shoots with more than 38 leaves exhibited the highest TSS (18.36%) and TSS/TA (250.81).【Conclusion】Based on the findings, a robust standard for fruit-bearing shoots in 'Xianjinfeng' litchi was determined as having a length greater than 14.5 cm, diameter greater than 0.5 cm, and number of leaves greater than 38. [ABSTRACT FROM AUTHOR]

The utilization of unmanned aerial vehicles (UAVs) for the precise and convenient detection of litchi fruits, in order to estimate yields and perform statistical analysis, holds significant value in the complex and variable litchi orchard environment. Currently, litchi yield estimation relies predominantly on manual rough counts, which often result in discrepancies between the estimated values and the actual production figures. This study proposes a large-scene and high-density litchi fruit recognition method based on the improved You Only Look Once version 5 (YOLOv5) model. The main objective is to enhance the accuracy and efficiency of yield estimation in natural orchards. First, the PANet in the original YOLOv5 model is replaced with the improved Bi-directional Feature Pyramid Network (BiFPN) to enhance the model's cross-scale feature fusion. Second, the P2 feature layer is fused into the BiFPN to enhance the learning capability of the model for high-resolution features. After that, the Normalized Gaussian Wasserstein Distance (NWD) metric is introduced into the regression loss function to enhance the learning ability of the model for litchi tiny targets. Finally, the Slicing Aided Hyper Inference (SAHI) is used to enhance the detection of tiny targets without increasing the model's parameters or computational memory. The experimental results show that the overall A P value of the improved YOLOv5 model has been effectively increased by 22%, compared to the original YOLOv5 model's A P value of 50.6%. Specifically, the A P s value for detecting small targets has increased from 27.8% to 57.3%. The model size is only 3.6% larger than the original YOLOv5 model. Through ablation and comparative experiments, our method has successfully improved accuracy without compromising the model size and inference speed. Therefore, the proposed method in this paper holds practical applicability for detecting litchi fruits in orchards. It can serve as a valuable tool for providing guidance and suggestions for litchi yield estimation and subsequent harvesting processes. In future research, optimization can be continued for the small target detection problem, while it can be extended to study the small target tracking problem in dense scenarios, which is of great significance for litchi yield estimation. [ABSTRACT FROM AUTHOR]

An unusual infestation of litchi fruit by the non-marine snail, Rhachis bengalensis (Lamarck, 1822) was the first time observed in litchi cultivating orchards in Muzaffarpur during May and June of 2019. In India, infestation and damage to vegetable and fruit crops by Achatina fulica (Bowdich), Pila globose (Swainson), Indosuccinea semiserica (Gould) were previously reported by many scientists. Achatina fulica was previously reported to cause severe damage to papaya, brinjal, beans, okra, rubber buds and guava while P. globosa was reported as a devastating pest of paddy and legume crops. The R. bengalensis was for the first time observed to infest litchi by sucking sap and feeding on the pulp of cracked litchi fruit during long periods of extremely warm weather. Results showed moderate infestation and an average of more than five snails was found per litchi plant. The damage caused by R. bengalensis through sucking sap and feeding pulp that led to abrasions on fruits and caused fungal contamination through their faces and slim wrinkle marks or deep slash mark on the pulp indicates the mode of infestation. In the host choice, the snails preferred cracked ripen litchi fruits more than others. [ABSTRACT FROM AUTHOR]

The pericarp browning and postharvest microbiological decay of litchi fruit (Litchi chinensis Sonn cv Kwai Mai) significantly reduce its commercial potential in the fresh market. In this study, different combinations of modified atmosphere packaging (MAP) were applied at 5 ± 1 °C based on the use of natural gases that are innocuous to human health and an alternative to commercially adopted sulfur dioxide (SO2) treatment. The results showed that control fruits, after 6 days of storage, begin to show the first symptoms of decay, revealed by the appearance of lesions and microbial infections determined by total mesophilic microorganisms and molds. This is not the case in the MAP-treated fruits and the MAP 3-treated (5% O2 + 20% CO2 + 75% N2) fruits that show the best results. The control fruits, moreover, turned completely brown by the end of the storage period. The MAP 3 treatment was the most effective in preventing browning and the loss of the red pericarp color and vitamin content and in maintaining acceptable SSC/TA levels and flavor. In addition, a microbiological analysis revealed that all the MAP-treated litchi fruits did not harbor undesirable microorganisms during the entire cold storage period. In conclusion, the MAP 3 conditions delayed pericarp browning and maintained the better organoleptic quality of litchi fruits. [ABSTRACT FROM AUTHOR]

A high-speed camera was applied to observe the shaking detachment tests with 'Guiwei' litchi clusters using 7 Hz, 9.5 Hz, and 12 Hz and the amplitudes of 40 mm, 60 mm, and 80 mm. The fruit's detachment time and the number of fruit–fruit impacts were affected by the vibrational parameters and the fruit position (inside or outside of the cluster). A high and stable detachment speed and a low number of impacts could be achieved with the parameter combination of 9.5 Hz/80 mm. The cluster index, considering both the shaking position and the total fruit mass, was found to have a stronger correlation with the detachment time than the average fruit-to-shaker distance (distance from the shaker to the fruit). Thus, the detachment time can be estimated based on the cluster indexes. The fruit-to-shaker distance also affected the fruit-to-shaker impact. A fruit-to-shaker distance of 50~60 mm was recommended to avoid almost all the impacts, depending on the shaking parameters. The horizontal throw distance of the fruit was calculated based on the detachment velocity and angle, which can be used as the design basis for the catching devices. With a high enough drop height, a disc-shaped catching surface with a radius of 475 mm, 489 mm, 591 mm, 741 mm, 844 mm, and 832 mm, respectively, could collect 90% of all the fruit at six different vibrational parameter combinations. A closer catching surface to the fruit could effectively reduce the horizontal throw distance. [ABSTRACT FROM AUTHOR]

Fruit abscission is a severe hindrance to commercial crop production, and a lack of carbohydrates causes fruit abscission to intensify in a variety of plant species. However, the precise mechanism by which carbohydrates affect fruit setting potential has yet to be determined. In the current study, we noticed negative correlation between hexose level and fruit setting by comparing different cultivars, bearing shoots of varying diameters, and girdling and defoliation treatments. The cumulative fruit-dropping rate was significantly reduced in response to exogenous glucose dipping. These results suggested that hexose, especially glucose, is the key player in lowering litchi fruit abscission. Moreover, five putative litchi hexokinase genes (LcHXKs) were isolated and the subcellular localization as well as activity of their expressed proteins in catalyzing hexose phosphorylation were investigated. LcHXK2 was only found in mitochondria and expressed catalytic protein, whereas the other four HXKs were found in both mitochondria and nuclei and had no activity in catalyzing hexose phosphorylation. LcHXK1 and LcHXK4 were found in the same cluster as previously reported hexose sensors AtHXK1 and MdHXK1. Furthermore, VIGS-mediated silencing assay confirms that LcHXK1 suppression increases fruit abscission. These findings revealed that LcHXK1 functions as hexose sensor, negatively regulating litchi fruit abscission. [ABSTRACT FROM AUTHOR]

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Aroma is considered a fundamental component of fruit flavor. Variations in the composition and content of volatile organic compounds (VOCs) contribute to noticeable differences in fruit aromas. Litchi is a delicious tropical and subtropical fruit, and a large number of germplasm resources with unique aromas have emerged during the past 2000 years of cultivation. In this review, our aim is to collect, compare, integrate, and summarize the available literature on the profiles of VOCs of 25 litchi cultivars. We showed that a total of 556 VOCs were reported from litchi fruit, and the aroma of litchi is mainly determined from the content and composition of monoterpenoids and alcohols, including linalool, geraniol, limonene, terpinolene, β-citronellol, p-cymene, nerol, α-terpineol, cis-rose oxide, β-myrcene, 4-terpineol, citral, and neral (cis-citral), which might contribute to the rose-like or citrus-like aroma of litchi fruit. Moreover, sulfur-containing volatile compounds (VSCs) possibly impart a special flavor to litchi fruit. This review would be a valuable resource for researchers aiming to improve litchi aroma quality by elucidating the possible mechanisms underlying VOC biosynthesis and their metabolism in litchi fruit. [ABSTRACT FROM AUTHOR]

This study aimed to provide a reference for the practical use of forchlorfenuron (CPPU) in the improvement of fruit set and quality (especially size) in litchi (Litchi chinensis Sonn.). CPPU at 5 mg/L was sprayed to fruit clusters of 'Feizixiao' at 2, 4, 6 and 8 weeks after female bloom (WAFB) in 2017 and at 2, 4, 6, 8, 9 or 10 WAFB in 2018, with spraying water as the control. The treatments were all effective at suppressing fruit abscission, resulting in higher fruit retention at harvest. Except for treatment at 2 WAFB, which caused stunted fruit and significantly reduced fruit weight, all the treatments had no significant influence on fruit weight and flesh (aril) weight, although CPPU tended to increase pericarp weight and strongly suppressed fruit coloration, and such effects were most significant in treatments at 4, 6 and 8 WAFB. Content of total soluble solids (TSS) in commercially ripe fruit (11WAFB) was not significantly influenced by CPPU applied at any of the stages. Ripe fruit continued to gain redness but lost TSS as it became overripe. CPPU suppressed redness gaining, the effect being stronger in later application. The treatments did not influence TSS loss, but treatments at 4, 6 and 8 WAFB significantly reduced the increase in fruit membrane leakage. In treatment at 6 WAFB, CPPU residue in the pericarp decreased sharply with time but relatively constant in the aril, where it maintained lower than 10 μg/kg, the maximal residue limitation in Australia and the United States. The results suggest that 5 mg/L CPPU is effective at improving fruit set and suppressing fruit pigmentation but has no significant effect on fruit size and TSS accumulation or maintenance in litchi. [ABSTRACT FROM AUTHOR]

The type and content of organic acids in fruits are important factors that determine the traits, such as the nutrition and flavor of fruits. Fruit weight and size are also very important economic characters in fruit breeding research. To investigate the inheritance patterns in longan, fruit organic acid contents, weight, and size were measured in the distant hybridization progenies of longan 'Huanongzao' and lychee 'Ziniangxi'. The results revealed that the malic acid accumulation exhibited mid-parent heterosis, citric acid content showed a tendency towards depression, and oxalic acid, ketoglutaric acid, fumaric acid, gallic acid, and total acid contents exhibited transgressive inheritance. The inheritance patterns in fruit weight, length and diameter tended towards smaller and degraded. The coefficient of variation (CV) for the organic acids ranged from 35.77–90.20%, and the heritability (H2) was 72.35–97.44%. High CV (55.44%) coupled with medium H2 (28.72%) were observed in fruit weight, however, low CV (12.29% and 12.50%) coupled with high H2 (68.95% and 69.25%) were shown in fruit length and diameter. In this study, the genetic variation of acid contents, fruit weight and size in the F1 population of longan and lychee were analyzed for the first time, providing an informative and theoretical basis for the selection and breeding of longan cultivars. [ABSTRACT FROM AUTHOR]

The present experiment was carried out at Horticulture Research Centre, Patharchatta, G.B. Pant University of Agriculture and Technology, Pantnagar during the year 2018-19 and 2019-20 to study the efficacy of different natural formulations in comparison with chemical insecticide chlorantraniliprole against litchi fruit borer. During both the years, least (1.27/panicle) and highest population (3.86/panicle) of borers were found in chlorantraniliprole treated plants and untreated plants respectively. Amongst the natural formulation Panchagavya was found most effective followed by neemastra, NSKE, dashparni, vermiwash and lantana with 1.61, 1.93, 2.23, 2.58, 2.90 and 3.25 borers/ panicle, respectively. Natural formulations were found at par with the chemical insecticide. Litchi plant relies heavily on natural enemies for pest control. These natural formulations used in the present experiment are safe to the natural enemies and can suitably be used as an alternative to chemical insecticides for management of litchi fruit borer. [ABSTRACT FROM AUTHOR]

Fruit color is a decisive factor in consumers' preference. The bright red color of litchi fruit is associated with its high anthocyanin; however, poor fruit coloration is a major obstacle in litchi plantation. The role of spraying mineral nutrient salts such as KH2PO4, KCl, K2SO4, and MgSO4 on litchi pericarp pigmentation was examined by a field trial, and the relation between human visual color preference versus pericarp pigments and hue-saturation-brightness (HSB) color parameters was investigated. K2SO4-sprayed litchi fruit gained the maximum popularity for its attractive red color. Spray of K and Mg salts decreased the buildup of yellowish pigments, but increased the accumulation of red ones, with the exception of slightly reduced anthocyanins in KH2PO4-sprayed fruit, by regulating the activities of enzymes involved in anthocyanidin metabolism and decreasing pericarp pH, leading to varied pericarp pigment composition. K2SO4 spray generated the highest percentage of cyanidin-3-glucoside over all pigments in pericarp. Correlation analysis shows the percent of cyanidin-3-glucoside, superior to anthocyanin concentration and HSB color parameters, was a reliable indicator to fruit color preference. This work demonstrates that spray of suitable mineral salt can regulate pericarp pigment profile, and is an effective approach to improve fruit pigmentation and promote its popularity. [ABSTRACT FROM AUTHOR]

To determine the heat unit requirement and assess its subsequent effects on flowering and fruiting characteristics, a field experiment was conducted during 2018-19 with seven cultivars of litchi viz., Calcuttia, Elaichi, Bedana, Bombai, China, Shahi and Muzaffarpur in randomized block design. Bedana showed better result in terms of maximum fruit weight (17.88g), lowest seed content (10.84%), maximum fruit diameter (3.01 cm), maximum fruit volume (18.70 ml), highest TSS (15.870 Brix), total sugar (15.96%), reducing sugar (12.61%), and ascorbic acid (29.47 mg/100g) content. [ABSTRACT FROM AUTHOR]

Bombai' is a popular litchi variety of West Bengal but susceptible to fruit cracking which reduces the market price. Till now numbers of research trial conducted in litchi with different chemicals but reports on impact of application of brassinolide in reduction of fruit cracking maintaining quality attributes are limited. Therefore, an experiment was conducted during January-May of 2019-20 at the Experimental Farm of Horticultural Research station, Mondouri, Bidhan Chandra Krishi Viswavidayala, Nadia, West Bengal, India to evaluate the effect of different dose of brassinolide on fruit yield, quality and reduction of cracking in litchi. The experiment was laid out in randomized block design comprising five treatments of brassinolide [T1: Brassinolide (0.5 mg l-1), T2: Brassinolide (1.0 mg l-1), T3: Brassinolide (1.5 mg l-1), T4: Brassinolide (2.0 mg l-1) and T5: Control (water spray)] with four replication/treatment. The solutions were applied two times; first before anthesis and another at 15 days after anthesis. Result revealed that brassinolide increased the number of fruits per panicle and significantly increased individual fruit weight, length, diameter, and yield. Among different treatments, brassinolides at 1 mg l-1 (two-time application i.e., 15 days before and after anthesis) is identified to be superior considering all qualitative aspects i.e., maximum fruit weight (26.40 g), fruit length (5.15 cm) and yield (95.88 kg plant-1). This treatment also exhibited maximum TSS (21.22°Brix), total sugar (14.11%), ascorbic acid (37.42 mg 100 g-1) and anthocyanin (23.13 mg 100 g-1) content with minimum (9.12%) fruit cracking. The control treatments registered minimum values for all parameters. [ABSTRACT FROM AUTHOR]

To address the automatic detection of dense and small-scale fruit targets under natural large-scene conditions, litchi was used as the research object. Here, a method to automatically detect dense and small-scale litchi fruit targets based on the YOLOv4 detection network is proposed. First, the K-means++ algorithm was used to cluster the labelled data frames (ground truth) to determine the size of the anchor suitable for litchi. Then, the output size of the feature map of the original network was changed to make it more suitable for small-scale target detection. In addition, the images were preprocessed (cropped input) before they were fed into the network. To construct the litchi dataset, 400 images containing more than 20,000 targets were collected. Comparing the detection level to that of the original YOLOv4 model, the recall, precision, and F1 score values of the improved model increased from 0.81 to 0.825, 0.762 to 0.892, and 0.79 to 0.85, respectively. The experimental results indicate that the performance of the litchi detection method proposed in the study is significantly greater than the original model, and it meets the requirements for fruit monitoring in litchi orchards. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Litchi is a highly perishable fruit. Ripe litchi fruit loses quality quickly as they hang on tree, giving a very short hanging life and thus harvest period. This study attempted to explore the roles of cytokinin in regulating fruit ripening and senescence of litchi and examine the possibility of applying cytokinin in "on-tree storage" of the fruit. Exogenous cytokinin, forchlorfenuron (CPPU), was applied at 20 mg L−1 7 weeks after full bloom on litchi (Litchi chinensis cv. Feizixiao) fruit clusters. Color parameters, chlorophylls, anthocyanins, fruit and fruit part weights, total soluble solutes (TSSs), soluble sugars, organic acids, non-anthocyanin flavonoids, ethanol, and also CPPU residue in fruit were traced. CPPU residue was higher but decreased faster in the pericarp than in the aril, where it maintained < 10 μg kg−1. CPPU had no significant effect on fruit weight but tended to increase pericarp weight. The treatment suppressed chlorophyll loss and anthocyanin accumulation in the pericarp, increased non-anthocyanin flavonoids in the aril, but had no significant effects on non-anthocyanin flavonoids in the pericarp and total sugar and organic acids in the aril. As the commercially ripe fruit hanged on tree, TSSs, total sugar, and sucrose decreased with ethanol and acetic acid accumulation in the aril. CPPU significantly suppressed the loss of sucrose and total sugar and the accumulation of ethanol and acetic acid in the aril and inhibited malondialdehyde accumulation in the pericarp of the overripe fruit. Soluble invertase, alcohol dehydrogenase, and pyruvate decarboxylase (PDC) activity and gene expression in the aril were downregulated by CPPU. The results suggest that cytokinin partially suppresses the ripening process in litchi and is effective to slow quality loss in the overripe fruit on tree. [ABSTRACT FROM AUTHOR]

An experiment was conducted during 2017 and 2018 at active field gene bank of ICAR-National Research Centre on Litchi to assess the effect of open cross pollination and self-pollination on fruit set and fruit characteristics in litchi. Nine cultivars of litchi were selected for study and result indicated that fruit set ranged from 17.41 to 68.14 per cent with maximum in 'Ellaichi' and minimum in 'Shahi'. The only three cultivars 'Ajhauli', 'Dehradoon' and 'Rose Scented' carried out fruit (0.28, 0.41 and 2.11%, respectively) at harvest under self-pollination condition while all nine cultivars carried out fruit at harvest ranged from 1.23 to 3.16 with maximum in 'Rose Scented' and minimum in 'Dehradoon' under open cross pollination. 'Dehradoon' had shown 3.23 fold more fruit set at harvest under open cross pollination as compare to self-pollination, similarly 'Rose Scented' and 'Ajhauli' has shown 2.98 fold and 10.5 fold, respectively more fruit set at harvest compare to self-pollination. The fruit weight was heavier in all three cultivars 'Dehradoon' (21.46 g), 'Rose Scented' (20.37 g) and 'Ajhauli' (18.95 g) in open cross pollination as compare to self-pollinated 'Dehradoon' (19.67 g), 'Rose Scented' (18.89 g) and 'Ajhauli' (17.35 g). The relatively self-incompatible was observed in 'Late Large Red', 'Ellaichi', 'Dehradoon', 'Rose Scented' whereas severely self-incompatible was found in 'Shahi' and 'Ajhauli'. The completely self-incompatibility was observed in 'Trikolia', 'Dehra Rose' and 'Deshi'. [ABSTRACT FROM AUTHOR]

Plant peroxidases (POD) are involved in various physiological and biochemical processes. Currently, there are relatively few studies on the role of POD in regulating the antioxidant capacity and senescence of postharvest litchi. In this study, we assessed the effects of Bacillus siamensis strain N-1 on the physiology and antioxidant quality of litchi fruit stored at 25 ℃, and characterized the molecular function of LcPOD4 gene in regulating the senescence of litchi fruit. The results showed that N-1 treatment significantly suppressed the increase in ethylene production, electrolyte leakage, and malondialdehyde (MDA) but did not inhibit the respiration rate of litchi during storage. Meanwhile, N-1-treated fruit maintained higher levels of phenolics, flavonoids, and total antioxidant capacity (T-AOC) and lower levels of superoxide anions (O 2 -.) and hydrogen peroxide (H 2 O 2). In addition, N-1 treatment enhanced the activity of defense enzymes, including superoxide dismutase (SOD), peroxidase (POD), glutathione reductase (GR), and phenylalanine ammonia-lyase (PAL). The results of quantitative real-time PCR (qRT-PCR) showed that the expression of nine selected LcPOD genes was induced by N-1 treatment at later stages of litchi storage. LcPOD4 cloned from litchi fruit was located in the cell wall and membrane. Transient overexpression of the LcPOD4 gene in tomato and litchi fruits significantly enhanced POD activity and total phenolic and flavonoid contents while accelerating peel color change in the fruit. Collectively, our results indicate that LcPOD4 may contribute, at least partially, to the enhancement of antioxidant capacity in litchi fruit but does not retard peel browning and senescence. [Display omitted] • B. siamensis strain suppresses physiology changes except for respiration rate of litchi fruit. • B. siamensis improves litchi antioxidant quality by inducing defense enzyme activities and transcription levels. • LcPOD4 acts as positive regulator for enhancing antioxidant capacity of litchi fruit. [ABSTRACT FROM AUTHOR]

The sun burn and fruit cracking in litchi were high in 2019 (10.5% and 10.1%) when temperature was high with low rainfall during fruit growth while low in 2017 (1.9% and 3.7%) when temperature was low. Lack of soil moisture and high temperature reduced the fruit weight in Kasba cultivar by (26.2%) and rainfall induced cracking in the cultivars Bedana and Early Bedana. The cultivars having higher relative water content and cuticle thickness reflected in low fruit cracking and vice-versa. These results may be helpful to identify suitable cultivars for preventive measures to reduce sun burn and fruit cracking in litchi. [ABSTRACT FROM AUTHOR]

In order to achieve accurate detection of litchi fruits in their natural environment, a ripe litchi recognition method with a Red-Green-Blue Depth (RGB-D) camera, which can be used to estimate fruit yields, is proposed in this paper. First, both colour and depth images of litchis are collected using an image capturing system with an RGB-D camera. Then, redundant image information outside the effective picking range of the manipulator is excluded using depth image segmentation. Finally, the random forest binary classification model is trained employing colour and texture features to recognise litchi fruits. Simultaneously, an approach based on multi-scale detection and a non-maximum suppression Algorithm is proposed to further improve the fruit detection precision. Visual recognition experiments using the proposed method to recognize red and green litchis are designed, and the method achieves a recognition accuracy of 89.92% for green litchis and 94.50% for red litchis. • A method to recognize different varieties of litchis effectively was proposed. • Visual system was designed to avoid fruit misjudgment due to uneven illumination. • Depth segmentation proposed effectively improves recognition accuracy. [ABSTRACT FROM AUTHOR]

Accurate and reliable fruit detection in the orchard environment is an important step for yield estimation and robotic harvesting. However, the existing detection methods often target large and relatively sparse fruits, but they cannot provide a good solution for small and densely distributed fruits. This paper proposes a YOLOv3-Litchi model based on YOLOv3 to detect densely distributed litchi fruits in large visual scenes. We adjusted the prediction scale and reduced the network layer to improve the detection ability of small and dense litchi fruits and ensure the detection speed. From flowering to 50 days after maturity, we collected a total of 266 images, including 16,000 fruits, and then used them to construct the litchi dataset. Then, the k-means++ algorithm is used to cluster the bounding boxes in the labeled data to determine the priori box size suitable for litchi detection. We trained an improved YOLOv3-Litchi model, tested its litchi detection performance, and compared YOLOv3-Litchi with YOLOv2, YOLOv3, and Faster R-CNN on the actual detection effect of litchi and used the F1 value and the average detection time as the assessed value. The test results show that the F1 of YOLOv3-Litchi is higher than that of YOLOv2 algorithm 0.1, higher than that of YOLOv3 algorithm 0.08, and higher than that of Faster R-CNN algorithm 0.05; the average detection time of YOLOv3-Litchi is 29.44 ms faster than that of YOLOv2 algorithm, 19.56 ms faster than that of YOLOv3 algorithm ms, and 607.06 ms faster than that of Faster R-CNN algorithm. And the detection speed of the improved model is faster. The proposed model remits optimal detection performance for small and dense fruits. The work presented here may provide a reference for further study on fruit-detection methods in natural environments. [ABSTRACT FROM AUTHOR]

The litchi fruit borer, Conopomorpha sinensis (Bradley) (Lepidoptera: Gracillariidae), is one of the major destructive and main pest of litchi fruits in Southeast Asia, including Bangladesh. This experiment was carried out in three different litchi orchards to develop a bio-rational management strategy using insect growth regulators (IGRs) to control the population of C. sinensis. The effectiveness of emamectin benzoate 5%, buprofezin, lufenuron, lufenuron (5%) + emamectin benzoate (5%), and abamectin were evaluated on the basis of fruit damage, yield of undamaged fruit and size, % fallen fruit, and total number of larvae in fallen fruits in three different litchi orchards. In our results, treatment with buprofezin showed the lowest (13.3%) level of fruit damage, followed by lufenuron + emamectin benzoate, abamectin, emamectin benzoate, and lufenuron, all of which were statistically significant compared with the untreated control. Furthermore, the highest number of undamaged fruits rate and mean fruit length were 86.7% and 17.8 mm, respectively, for buprofezin treatment compared to control (75.5 and 16.2). A large number of damaged, fallen fruits were found in the control plots (11.3%), while their number was lowest in buprofezin-treated orchards (4.1%). The chemical composition of litchi fruits was not affected by the application of IGRs. Indeed, levels of vitamin C, sugars, and titratable acidity increased in IGR-treated fruits compared with fruits from the control plots. Moreover, IGR treatments had a positive effect on total phenol (except lufenuron + emamectin benzoate) and flavonoid content of litchi fruits, improving their quality and as a source of antioxidants. Therefore, buprofezin can be used to manage the litchi fruit borer in organic litchi orchards. [ABSTRACT FROM AUTHOR]